Origin of long-range order in a two-dimensional nonequilibrium system under laminar flows

We study long-range order in two dimensions where an order parameter is advected by linear laminar flows. The linear laminar flows include three classes: rotational, shear, and elongational flows. Under these flows, we analyze an ordered state of the $O(N)$ scalar model in the large-$N$ limit. We show that the stability of the ordered state depends on the flow pattern; the shear and elongational flows stabilize but the rotational flow does not. We discuss a physical interpretation of our results based on interaction representation in quantum mechanics. The origin of the long-range order is interpreted from the advection of wavenumbers along the streamlines and its stretching effect stabilizes the order.Comment: 6+5pages, 3+1figure

Universal properties of repulsive self-propelled particles and attractive driven particles

Motility-induced phase separation (MIPS) is a nonequilibrium phase separation that has a different origin from equilibrium phase separation induced by attractive interactions. Similarities and differences in collective behaviors between these two types of phase separation have been intensely discussed. Here, to study another kind of similarity between MIPS and attraction-induced phase separation under a nonequilibrium condition, we perform simulations of active Brownian particles with uniaxially anisotropic self-propulsion (uniaxial ABPs) in two dimensions. We find that (i) long-range density correlation appears in the homogeneous state, (ii) anisotropic particle configuration appears in MIPS, where the anisotropy removes the possibility of microphase separation suggested for isotropic ABPs [X.-Q. Shi et al., Phys. Rev. Lett. 125, 168001 (2020)], and (iii) critical phenomena for the anisotropic MIPS presumably belong to the universality class for two-dimensional uniaxial ferromagnets with dipolar long-range interactions. Properties (i)-(iii) are common to the well-studied randomly driven lattice gas (RDLG), which is a particle model that undergoes phase separation by attractive interactions under external driving forces, suggesting that the origin of phase separation is not essential for macroscopic behaviors of uniaxial ABPs and RDLG. Based on the observations in uniaxial ABPs, we construct a coarse-grained Langevin model, which shows properties (i)-(iii) and corroborates the generality of the findings.Comment: 10+9 page

Influence of implant length and diameter, bicortical anchorage, and sinus augmentation on bone stress distribution: Three-dimensional finite element analysis

Purpose: Clarification of the protocol for using short implants is required to enable widespread use of short implants as an available treatment option. The purpose of this study was to investigate the influences of implant length and diameter, bicortical anchorage, and sinus augmentation on peri-implant cortical bone stress by three-dimensional finite element analysis. Materials and Methods: For bone models with bone quantity A and C in the maxillary molar region, three-dimensional finite element analysis was performed using different lengths and diameters of implant computer-aided design models, and the degree of maximum principal stress distribution for each model was calculated. Results: For bone quantity A models, the degree of stress distribution of the 4-mm-diameter, 6-mm-length implant was the greatest. For bone quantity C models, the degree of stress distribution of the 5-mm-diameter, 6-mm-length implant with bicortical anchorage was much smaller than that for the 4-mm-diameter, 13-mm-length implant with sinus augmentation. Conclusion: The results of this study suggest that 6-mm-length implants should be selected in cases with bone quantity C where the bone width permits increasing implant diameter from 4 mm to 5 mm.Moriwaki H., Yamaguchi S., Nakano T., et al. Influence of implant length and diameter, bicortical anchorage, and sinus augmentation on bone stress distribution: Three-dimensional finite element analysis. International Journal of Oral and Maxillofacial Implants 31, 84 (2016); https://doi.org/10.11607/jomi.4217

1-Year Results of the ZEPHYR Registry (Zilver PTX for the Femoral Artery and Proximal Popliteal Artery) Predictors of Restenosis

AbstractObjectivesThis study sought to assess the rate and predictors of 1-year restenosis after drug-eluting stent implantation for femoropopliteal (FP) lesions in patients with peripheral arterial disease.BackgroundZilver PTX, a paclitaxel-eluting stent for FP lesions, provides superior outcomes to angioplasty and bare-metal stents in clinical trials. However, its real-world outcomes and the associated features remain unclear.MethodsThis was a prospective multicenter study enrolling 831 FP lesions (797 limbs, 690 patients) treated by Zilver PTX implantation. The primary endpoint was 1-year restenosis. Secondary endpoints included major adverse limb event and stent thrombosis.ResultsMean lesion length was 17 ± 10 cm. One-year restenosis, major adverse limb event, and stent thrombosis rates were 37%, 22%, and 2%, respectively. The generalized linear mixed model showed that lesion length ≥16 cm assessed by angiography and distal external elastic membrane area ≤27 mm2 and minimum stent area ≤12 mm2 assessed by intravascular ultrasound were independent risk factors for restenosis. One-year restenosis rates were 15% in cases with none of these risk factors and 50% in those with ≥2 risk factors.ConclusionsThe current study demonstrated 1-year real-world outcomes after drug-eluting stent treatment for FP lesions, including challenging ones in clinical practice. Lesion length, external elastic membrane area, and minimum stent area were independent predictors for restenosis. (Zilver PTX for the Femoral Artery and Proximal Popliteal Artery—Prospective Multicenter Registry [ZEPHYR]; UMIN000008433

Association between antispasmodics and detection of lesions by screening esophagogastroduodenoscopy

BACKGROUND AND AIM: Whether administration of antispasmodics as a component of premedication contributes to detection of lesions by screening esophagogastroduodenoscopy (EGDS) remains unclear. Our primary aim was to investigate this possibility. METHODS: The cohort in this retrospective study comprised consecutive asymptomatic individuals who had undergone screening EGDS as part of a health check-up at the Japanese Red Cross Wakayama Medical Center from October 2015 to September 2020. The investigated lesions comprised esophageal squamous cell carcinoma or adenocarcinoma, gastric adenoma or adenocarcinoma, and duodenal adenoma or adenocarcinoma. RESULTS: Targeted lesions were detected in 72 of 31 484 participants (0.23%), 18 260 and 13 224 of whom had received and not received pre-procedure antispasmodics, respectively. The rates of detection of lesions in these groups were 0.21% (38/18260) and 0.26% (34/13224), respectively (P = 0.40). Multivariate logistic regression analysis showed no association between administration of antispasmodics and rates of detection of targeted lesions [P = 0.24, Odds ratio (95% CI): 1.46 (0.78-2.75)]. CONCLUSIONS: Antispasmodics, which were administered to more than half of the study cohort, did not improve the rate of detection of targeted lesions